Traditional naval blockade is carried out with sea mines. However sea mines suffer from its relative ease of being detected and immobility. Sea mine sweeping vessels are able to neutralize sea mines with mature techniques. Earlier in the military history, iron chains were used to deny access to a port or a city. However in modern warfare, chain blockade ceases to be a practical means to achieve effective blockade. Submarines are frequently used to stealthily patrol a vast water territory and carry out strategic or tactical attack missions. As a tactical weapon, submarines have proved highly effective since its invention. However, submarines are typically manned and very expensive. Furthermore, detection of submarine has greatly improved over the years, which makes submarines more vulnerable. There is a pressing need to have an inexpensive, stealthy, powerful and smart marine weapon that is able to carry multiple types of missions.